This application claims the benefit of Japanese Patent Application No. 2003-381546, filed Nov. 11, 2003, which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a stacking-type, multi-flow, heat exchanger comprising heat transfer tubes and fins stacked alternately. Specifically, the present invention relates to an improved structure of a stacking-type, multi-flow, heat exchanger suitable as a heat exchanger, in particular, as an evaporator, for use in an air conditioner for vehicles.
2. Description of Related Art
A stacking-type, multi-flow, heat exchanger having alternately stacked heat transfer tubes and fins is known in the art, for example, as an evaporator for an air conditioner in vehicles. Recently, however, size limitations imposed on air conditioners for smaller vehicles have become more restrictive as a result of the reduced space available in vehicles. In particular, for an evaporator, the size limitations have been reduced for both the width of the evaporator in the stacking or transverse direction of the tubes and fins and for the thickness of the evaporator in the air flow direction. To satisfy such requirements, a structure of a stacking-type, multi-flow, heat exchanger has been proposed, in which a side tank for forming a fluid introduction passage and a fluid discharge passage are provided at an end of a heat exchanger core in the stacking direction of the tubes and fins. A heat exchange medium is introduced into and discharged from the heat exchanger core at a side of the heat exchanger by connecting a flange member having fluid introduction and discharge pipes to the side tank, and the thickness of the heat exchanger is reduced by employing a structure with no flange and no fluid introduction and discharge pipes on the front and rear surfaces of the heat exchanger (for example, Japanese Patent No. 2000-283685).
Further, in such a structure, in order to further reduce the thickness of the heat exchanger, and because the flange member may protrude from the heat exchanger core, a structure, as depicted in FIGS. 7–10, has been proposed, in which the flange member is disposed to be inclined obliquely relative to the height direction (the tube extending direction) of the heat exchanger (for example, Japanese Patent No. 2001-56164).
In FIGS. 7–10, a heat exchanger 100 has a heat exchanger core 103 formed by heat transfer tubes 101 and outer fins 102 stacked alternately. Tanks 104 and 105 are provided at either end of heat transfer tubes 101 (the upper and lower ends in FIG. 7), respectively. Each heat transfer tube 101 is formed by a pair of tube plates 106 and 107 connected to each other, and tanks 104 and 105 are formed at either end of heat transfer tubes 101 by stacking a plurality of heat transfer tubes 101.
An end plate 108 is connected to an outermost fin 102 in the stacking or transverse directions by brazing. A side tank 109, as depicted in FIG. 10, is connected to end plate 108. A flange member 111 is connected to side tank 109 via a flange stay 110. Flange member 111 includes an inlet pipe 112 for introducing a heat exchange medium into an inlet tank portion of tank 104 through side tank 109, an outlet pipe 113 for discharging heat exchange medium from an outlet tank portion of tank 104 through side tank 109, and a flange body 114. As depicted in FIG. 9, inlet and outlet pipes 112 and 113 and flange body 114 are formed integrally. For example, flange member 111 may be formed by machining a single block of material.
As depicted in FIGS. 9 and 10, an insertion hole 115, into which inlet pipe 112 of flange member 111 is inserted, and an insertion hole 116, into which outlet pipe 113 of flange member 111 is inserted, are formed in side tank 109. In FIG. 10, insertion hole 115 is disposed at a right lower position relative to insertion hole 116. Therefore, as depicted in FIG. 8, flange member 111 is connected to side tank 109 at an inclined orientation relative to the height direction h of heat exchanger 100. In such a structure, while preventing inconvenience caused by the protrusion of flange member 111 in the thickness direction t of heat exchanger 100 (in the left/right direction of FIG. 8, namely, an air flow direction as depicted by an arrow in FIG. 8), a further reduction in the size of heat exchanger 100 may be achieved.
In such a structure, however, as depicted by an arrow line in FIG. 7, the heat exchange medium introduced into inlet pipe 112 of flange member 111 impinges on end plate 108 forming one side wall of side tank 109, the flow direction of the heat exchange medium is changed by an angle of 90 degrees, the heat exchange medium flows upward in side tank 109, the flow direction of the heat exchange medium is changed by an angle of 90 degrees again at an upper portion in side tank 109, and then, the heat exchange medium flows into tank 104. Such a flow path may increase the pressure loss. Further, although the thickness of side tank 109 is increased in order to ensure sufficient cross-sectional area of the passage in side tank 109 to suppress the pressure loss in the side tank 109, in this case, the width of heat exchanger 100 (the stacking or transverse direction s of heat exchanger 100 in the left/right direction in FIG. 7) may increase. Consequently, controlling pressure loss in heat exchanger 100 may interfere with efforts to reduce heat exchanger size, conserve space for heat exchanger installation, and reduce heat exchanger weight. Moreover, because flange member 111 may be processed by machining a single block of material, it may be necessary to provide a certain wide gap between inlet pipe 112 and outlet pipe 113 for insertion of a turning tool. Therefore, it may be difficult to reduce a length l (depicted in FIG. 8) of flange member 111 in the arrangement direction of the inlet and outlet pipes, and it may be difficult to respond to the requirement for a further reductions in the size of heat exchanger 100.